Pierre asked:

Could you explain to me induction versus falsification?

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I'm not totally sure what you're actually asking, though the wording suggests to me that you have in
mind the collecting of evidence with a view to elaborating hypotheses or theories from this information
(i.e. what Bacon meant when he dealt with this issue). It is not a sound philosophical principle (cf.
Hume), but it works sufficiently well in a practical scientific setting and in many cases with such high
probability of assurance that it would be churlish (as well as impractical) to deny the validity of the
principle as a default methodology for science. Problems arise when scientists presume on the
strength of any hypothesis or theory that may have been derived inductively to work out a proof
positive in their favour. It is then that falsification enters the picture. But to appreciate what's at issue,
you can't restrict yourself to science, where induction is in any case more preached than practised.
You need to look at the philosophical backdrop, from where the concept of falsification arose in the
first place.

Now the historical setting for this is Vienna in the 1920s and a group of thinkers collectively known as
the 'Viennese Circle', whose philosophy goes by the title 'logical positivism'. Most of their members
are forgotten names today; at most you might still come across Rudolf Carnap now and then, who
was the leading light of the group. Put in the plainest terms, their doctrine was that knowledge is what
can be established by watertight proof: so any theory purporting to be true needed to accumulate and
then evaluate the evidence and, of course, both accumulation and evaluation relied on scientific tests
for validation. A programme, one might say, as old as the hills; yet because these men brought their
doctrines to bear on philosophy and indeed attacked philosophy for admitting such slipshod
disciplines as metaphysics into its canons, the Vienna Circle achieved reknown and respect, and
thinkers of the calibre of Wittgenstein and Russell did not disdain association with them, at least for
some time.

The euphoria, however didn't last long — except in the public domain where, if today you see an
advertisement for makeup or washing powder, where science is supposed to have proved the benefit
of using a particular substance, that is a legacy of logical positivism. The problem is, of course, that
science cannot possibly prove such a thing; in fact, the whole philosophical issue involved here is that
science cannot prove, 'incontrovertibly and positively', anything whatever. The man who spotted the
chink in this reasoning was the young Karl Popper, then loosely associated with the Circle, though
never a member.

Popper himself only claims that his reading of Hume made him realise that the tenets of logical
positivism were shown to be unsound by Hume 200 years before the Viennese brought them up, in
full ignorance of this historical fact. The point he nailed down (on Humean precedent) was that you
can observe what you will as many times as you wish, nevertheless phenomena confer no
guarantees.It is an in-principle impossibility. From this realisation sprang his idea that a theory based
on hard, factual and experimentally tested evidence may yet be accepted as true (for the time being)
for as long as it has not been disproved,or, as he termed it, falsified.In short, he realised that
phenomena do after all guarantee one thing: they return a 'positive false' to mistaken experiments!
According to Popper, this is the best we can have: if a theory stands up to repeated blistering
attempts at demolishing it, then we may confidently pronounce it as 'true', though always and ever
only interimistically. Contrary therefore to the beliefs of the Vienna Circle, a theory is not established
by positive evidence and experiment, but by resisting every effort at falsification.

To pursue this as an interest, obviously Popper's writings would be the best source: always get it from
the horse's mouth if you can. The best, though a difficult text, is Objective Knowledge.But it's worth
the effort.

Jürgen Lawrenz

Sydney